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1. Grab the picture of your favorite candy 2. And the Charles Darwin Article ◦ Read the Article and summarize each paragraph off the side ◦ When you are finished answer the questions on the back Be prepared to share your answers At your table In groups of 3 Discuss your answers and accumulate them into one on a white board. Make sure to add other students notes to your own CSCOPE Unit:09 Lesson: 01 Students = Predators Candy = different populations of organisms On your white boards describe the traits (characteristics) your candy has Differential Reproductive Success 1. 2. 3. 4. 5. 6. What is variation? What is genetic variation? Which candy “population” was most “fit” for it’s environment? What do you think will eventually happen to the skittle population is the trend continues? How do I know the more fit “species” passed on their genes? Did individual species change? Why or why not? In your spirals write this Variation occurs in all populations and because of this, some individuals will be more fit to reproduce than others. Answer the following Question. How does genetic variation lead to (Differential) reproductive success? Genetic variation means each individual has unique traits; some traits will help an individual survive and reproduce, and some traits do not. Differential Reproductive Success A E D Reproductive Success Natural Selection B F C Limited Resources Fitness Genetic Variation Reproductive Success Natural Selection Organisms produce more offspring than can survive. Competition Environmental Factors Natural Selection Lab Sheet Do not throw the beads. THIS IS A LAB. ALL LAB BEHAVIOR is required by law. Candy = different populations Students = predators Answer the Lab Analysis Questions 1. 2. 3. 4. 5. Was genetic variation was present in the population? If so, how? What did this variation lead to in the population? How do you know the successful traits are passed on? Did my individual species change? Explain. What changed overtime and how did it change? 1. 2. 3. 4. 5. Evolution Foldable Chart Formula for Natural Selection Types of Natural Selection Chart Glue Scissors Set up the Mechanisms of Evolution Foldable Complete Formula for Natural Selection Complete Natural Selection Chart with Graphs If we have time Grade Natural Selection Lab and Graphs Steps: 1. Remove the excess paper from the top and bottom by cutting along the dotted lines shown below in red. 2. Fold along the center line shown in red below. 3. Cut along the dotted lines between each box. Stop cutting where the dotted lines end. 4. Fold along the red dotted lines shown below so that each box folds open. 5. Glue the section highlighted in yellow below in your spiral (right side) so that only the tabs will fold open. LEAVE ROOM IN YOUR SPIRAL FOR DEFINITIONS! We are going to study mechanisms that aid in evolution. Evolution – a change in the more successful inherited traits within a population over generations A species is an organism(s) that can produce fertile offspring A population is a group of 2 or more of the SAME organism Natural Selection Mutations Recombination Gene Flow Genetic Drift Artificial Selection Non-Random Mating Reproductive Isolation 1. 2. 3. 4. ON PAGE 1 Cut out the graphic organizer Fold along the middle line then Cut the tabs on the dotted lines. ON PAGE 2 Cut out the images, definitions, and terms that will be glued onto the graphic organizer. Work with a partner to determine where the 1. terms, 2. definitions, and 3. images Fit on the graphic organizer. The images & definitions will go under the tabs The terms go in the “formula” on the front. “Natural Selection” has already been correctly placed in the “formula”. What is the purpose of using the “formula” model to help explain natural selection? The purpose of the formula is to show that Natural Selection cannot occur without one step causing the next step which leads to natural selection and causes Evolution. What three things are needed for the process of natural selection? For Natural selection to occur Variations + Reproductive Success + heredity (inheritance) are needed. What sort of things cause variation in a population? Reproduction, Meiosis (genetic recombination), & mutations can cause variations within a population. Title notes Types of Natural Selection and Adaptations In your Spirals write these 2 statements about Natural Selection and Adaptations 1. 2. An adaptation is – characteristic common in a population because it provides an improved function. Adaptations are the result of natural selection. The most successful traits are passed on to future generations. Type Directional Selection Disruptive Selection Stabilizing Selection Definition Result Phenotypic Range According to the graph what is the most common phenotype? Light? Medium? Dark? Type Directional Selection Disruptive Selection Stabilizing Selection Definition Result Type Directional Selection Disruptive Selection Stabilizing Selection Definition A process of natural selection in which a single phenotype at one extreme of the phenotypic range is favored Result The population's trait distribution shifts toward an extreme. Type Definition Result Directional Selection A process of natural selection in which a single phenotype at one extreme of the phenotypic range is favored The population's trait distribution shifts toward an extreme. Disruptive Selection A process of natural selection that favors individuals at both extremes of a phenotypic range Can cause such differences among a species that the variation leads to new species (SPECIATION) Stabilizing Selection Type Definition Result Directional Selection A process of natural selection in which a single phenotype at one extreme of the phenotypic range is favored The population's trait distribution shifts toward an extreme. Disruptive Selection A process of natural selection that favors individuals at both extremes of a phenotypic range Can cause such differences among a species that the variation leads to new species (SPECIATION) Stabilizing Selection A process of natural selection that tends to favor genotypic combinations that produce an intermediate phenotype It reduces phenotypic variation. Natural selection tends to remove the more severe phenotypes. (minimal or no change) In groups of 3 Decide which graph is 1. Disruptive 2. Directional 3. Stabilizing Natural Selection Look back at your graphic organizer. We will be exploring the following processes and their influence on population change (evolution): ◦ ◦ ◦ ◦ ◦ ◦ Natural Selection Mutations Gene flow Genetic drift Artificial selection Non-random mating We’ll explore recombination and reproductive isolation later. The circles on your boards help distinguish the original population makeup from what it might look like after the change and its makeup many, many generations later. The dots represent individual organisms within the population. Original Population Instead of thinking about the dots as representing a single individual, think about them representing a percentages of individuals. For example, in the population shown below, about half of the individuals are red, a quarter are blue, and a quarter are green. That means that if 1,000 individuals made up that population, about 500 would be red, about 250 blue, and 250 green. Original Population Original Population After Chemical Spill Many Generations Later Original Population After Mutation Many Generations Later Real-World Examples: http://evolution.berkeley.edu/evosite/evo10 1/IIIC2aCasestudy.shtml Neighboring Population Original Population After Migration Many Generations Later Real-World Examples: http://evolution.berkeley.edu/evosite/evo101/IIIC4a Geneflowdetails.shtml Original Population After Lightning Many Generations Later Real-World Examples: http://www.bio.georgiasouthern.edu/biohome/harvey/lect/lectures.html?flnm=nsln&ttl=Popu lation%20change%20and%20natural%20selection&cco de=el&mda=scrn http://highered.mcgrawhill.com/sites/dl/free/0072835125/126997/animati on45.html Original Population Many Generations Later Real-World Examples: http://learn.genetics.utah.edu/content/variat ion/artificial/ Original Population Blue = BB or Bb Red = bb x Many Generations Later Real-World Examples: http://www.bio.georgiasouthern.edu/biohome/harvey/lect/lectures.html?flnm=nsln&tt l=Population%20change%20and%20natural%2 0selection&ccode=el&mda=scrn The models make it seem that these processes happen separately and exclusively from each other. The fact is that numerous mechanisms are simultaneously changing and molding the genetic makeup of a population. Population numbers in a real ecosystem are much larger than what we can represent with dots on our desk. The genetic makeup and allele frequencies in a population are much more complicated than blue, green, and red colors. These models are to help you understand the basic definitions and processes of evolution, but remember, genetic change on a population scale is MUCH, MUCH, MUCH more complex than these models can show. As we learned in the genetics unit, recombination leads to genetic material being shuffled. This shuffling, along with sexual reproduction, leads to variation within populations. This variation leads to selection, which ultimately leads to evolution. ◦ http://evolution.berkeley.edu/evolibrary/article/e vo_22 A new species may form when one population of a species becomes reproductively isolated from another population of the same species. Over time, evolutionary mechanisms occur that alter the gene pool of the isolated population so that it is no longer reproductively compatible with the original population. A group of individuals that actually or potentially interbreed in nature. A species is the biggest gene pool possible under natural conditions. Scientists group organisms according to their similarities. The most similar organisms belong to a species. Members of the same species can mate and produce fertile offspring. Ex: Humans belong to the species Homo sapiens. Speciation is a lineage-splitting event that produces two or more separate species. Since being a member of one species is defined by the ability to successfully reproduce, speciation (the formation of a different species) must involve an inability to successfully reproduce. Two way reproductive isolation occur: Prezygotic mechanisms Postzygotic mechanisms Temporal Isolation: Species reproduce in different seasons or at different times of the day. Geographical Isolation: Physical barriers (e.g., rivers, oceans, mountains) prevent the mixing of populations. Behavioral Isolation: Species differ in their mating rituals (e.g., differing bird songs, mating colors, dances, pheromones). Mechanical Isolation: Body structure prevents mating. Hybrid inviability: Embryological Arrest: Hybrid embryos often do not develop properly; no viable offspring is created. Hybrid Sterility: Infertility: Hybrid offspring might grow to viable adults, but these are infertile and cannot produce further offspring This shuffling, along with sexual reproduction, leads to variation within populations. This variation leads to selection, which ultimately leads to evolution. ◦ (Donkey + Horse = Mule; Mule is sterile.) Cladogenesis is the splitting of one species into two. How does this happen? o Geographical (physical) isolation, which leads to reproductive isolation. This is also known as allopatric speciation. There are two scientific theories regarding how evolution occurs. ◦ Punctuated Equilibrium: This theory proposes that throughout geological time, biological species go through long periods of little change and then have brief periods of rapid change. ◦ Gradualism: This theory proposes that throughout geological time, biological species gradually undergo changes that leads to speciation. Mechanisms of Evolution Evolution - _____________ _______________________________________________________________.